Device for treating a metal strip

ABSTRACT

The invention relates to a device for processing a metal strip ( 200 ) after said metal strip has exited a coating tank ( 300 ) having liquid coating material ( 310 ). Above the coating tank, the device has a blow-off apparatus ( 110 ) having an air outlet slot ( 112 ) for blowing liquid parts of the coating off of the metal strip. Arranged above the blow-off apparatus ( 110 ) is an electromagnetic stabilization apparatus ( 140 ) for stabilizing the metal strip by means of electromagnetic forces after the exiting of the coating tank and the blow-off apparatus. According to the invention, in order to design known devices for treating a metal strip to be more favorable in respect of energy and in order to increase the accessibility of said devices for an operating person, the stabilization apparatus ( 140 ) is arranged above the blow-off apparatus ( 110 ) in such a way that the distance d between the line of action of the maximum force of the stabilization apparatus on the metal strip and on the air outlet gap ( 112 ) of the blow-off apparatus ( 110 ) is limited to a range of 100-1200 mm.

The invention relates to a device for treating a metal strip after thishas exited a coating container with liquid coating material, for examplezinc.

Devices of that kind are basically known in the prior art, thus, forexample, from WO 2012/172648 A1 and German Patent Applications DE 102009 051 932 A1, DE 10 2007 045 202 A1 and DE 10 2008 039 244 A1. Inconcrete terms, these specifications disclose a coating container filledwith a liquid coating material. For coating, the metal strip isconducted through the container with the coating material. After leavingthe coating container the material strip runs through a blow-off deviceor a nozzle, which is arranged above the coating container, for blowingoff excess parts of the still-liquid coating material adhering to thesurface of the metal strip. Arranged above the blow-off device is anelectromagnetic stabilising device, which is supported by the blow-offdevice and which is also called dynamic electromagnetic coatingoptimiser (DEMCO), for stabilising the strip after leaving the coatingcontainer and the blow-off device. The electromagnetic stabilisingdevice generates electromagnetic forces, with the help of which themetal strip is kept centrally in a centre plane of the overall device;oscillation of the metal strip during transit of, in particular, theblow-off device is in this way at least reduced.

However, in these described constructions in reality there is thedisadvantage—apart from in the case of the construction according to DE10 2008 039 244 A1—that the electromagnetic stabilising device isarranged quite far above the blow-off device. This is disadvantageousinsofar as the stabilising effect, which is exerted by the stabilisingdevice, on the metal strip acts only to a limited extent at the blow-offdevice. Moreover, the forces which are to be generated by thestabilising device and which are necessary in order to stabilise themetal strip in the region of the distant blow-device are comparativelylarge in the prior art. Accordingly, energy consumption for operatingthe stabilising device is also comparatively high. Finally, it isdisadvantageous that the stabilising device is arranged above the nozzlesupport or the cross member, since as a consequence access to the metalstrip in the region of the nozzle support is significantly hampered.

The invention has the object of developing a known device for treating ametal strip in such a way that access to the metal strip in the regionof the nozzle support is significantly eased.

This object is fulfilled by the subject of claim 1.

By virtue of the claimed closer arrangement of the stabilising device tothe blow-off device it is advantageously achieved that less force has tobe generated by the stabilising device in order to stabilise the metalstrip in the region of the blow-off device or nozzle. The energyrequirement of the stabilising device is thereby also reduced and thedevice is more efficient overall.

A horizontal cross member, also called nozzle support, is mountedbetween two vertical posts. The blow-off device is secured to the crossmember to hang below the cross member. In addition, the stabilisingdevice is secured below the cross member to hang thereat, but betweenthe cross member and the blow-off device. The mounting of thestabilising device on the cross member is independent of the attachmentof the blowing-off device to the cross member.

The arrangement of not only the stabilising device, but also theblow-off device below the cross member offers the advantage that theregion above the cross member and thus also a slot, which is spanned bythe cross member, for passage of the metal strip is accessible in verysimple manner to an operator.

According to a first embodiment the respective individual securing ofthe blow-off device and the stabilising device to the cross member takesplace by way of independent displacing devices. In concrete terms, theblow-off device is secured to the cross member by way of a blow-offdisplacing device, but is displaceable relative to the cross member. Inaddition, the stabilising device is secured to the cross member by wayof the stabilising-displacing device, but is displaceable relative tothe cross member. The two displacing devices enable respectivelydifferent degrees of freedom for movement of the blow-off device and thestabilising device relative to the centre plane of the device and alsorelative to the metal strip.

In particular, the two devices enable displacement of the blow-offdevice and the stabilising device relative to one another. Apart fromthe individual degrees of freedom, which are realised by the blow-offdisplacing device and the stabilising-displacing device, for therespective devices it is advantageous that the cross member togetherwith the blow-off device and stabilising device suspended thereat ismounted on the vertical posts to be vertically movable. The verticalposts are displaceable together with the cross member parallel to oneanother in the horizontal plane. Because the cross member is mounted onone of the vertical posts to be pivotable in the horizontal plane abouta fixed fulcrum (fixed side) and the cross member is movably mounted onthe other vertical post (movable side), pivotation of the cross memberin the horizontal plane is also possible. These degrees of freedom ofthe cross member are applicable to the blow-off device and thestabilising device equally, since the two mentioned devices are securedto the cross member.

Accompanying the description are two figures, wherein:

FIG. 1 shows a width view of the device according to the invention,

FIG. 2 shows a cross-section through the device according to theinvention and

FIGS. 3 and 4 show plan views of the slot of the blow-off deviceaccording to the invention or of the electromagnetic stabilising deviceaccording to the invention, each with marking of the target centreposition and different desired actual positions of the metal strip.

The invention is described in detail in the following in the form ofembodiments with reference to the mentioned figures. In all figures, thesame technical elements are denoted by the same reference numerals.

FIG. 1 shows the device 100 according to the invention. It comprises twolateral, vertically extending posts 150, on which a cross member130—also termed nozzle support—is mounted to be vertically andhorizontally movable; see the double arrow in FIG. 1. The device 100 isadditionally pivotable in the horizontal plane. For this purpose, one ofthe two posts 150 is constructed as fixed side A on which the crossmember is mounted to be pivotable about a vertical axis of rotation. Bycontrast, the opposite post is constructed as movable side B andsupports the cross member merely vertically. Through this constructionof the posts as fixed side and movable side the device 100 and, inparticular, the cross member 140 can be oriented, in the case of askewed metal strip 200, symmetrically relative thereto by pivotation inthe horizontal. As a result, the wide sides of the cross member shallalways be aligned parallel to the metal strip and the two have the samespacing therefrom.

A blow-off device 110 or nozzle is suspended at the cross member 130.The coupling of the blow-off device 110 to the cross member 130 iscarried out not rigidly, but by way of a blow-off displacing device 115constructed to displace the blow-off device 110 relative to the crossmember 130 in the horizontal plane, i.e. in particular perpendicularlyto the centre plane 160 of the device. In addition, the blow-offdisplacing device 115 is constructed to pivot the blow-off device 110about its own longitudinal axis L and thus suitably adjust it relativeto the metal strip 200.

A stabilising device 140, also termed dynamic electromagnetic coatingoptimiser (DEMCO), is secured by way of a stabilising-displacing device145 to the cross member between the cross member 130 and the blow-offdevice 110. This stabilising-displacing device 145 enables translationaldisplacement of the stabilising device 140 in the horizontal planerelative to the cross member, in particular perpendicularly and parallelto the centre plane 160 of the device 100. In addition, thestabilising-displacing device 145 can also be constructed to pivot thestabilising device 140 in the horizontal plane relative to the crossmember 130 and relative to the blow-off device 110 about a vertical axisof rotation.

FIG. 2 shows the device of FIG. 1 according to the invention in across-sectional view. The reference numeral 170 denotes a control devicefor controlling the stabilising-displacing device 145. A coatingcontainer 300 can be seen, which is basically arranged below the device100. The metal strip 200 to be coated is conducted in transportdirection R into the coating container 300 with the liquid coatingmaterial 310 and deflected thereat into the vertical with the help of adeflecting roller 320. It then runs from the bottom to the top initiallythrough the blow-off device 110 and subsequently the stabilising device140. The present invention provides that the spacing d between the lineof action of the maximum force F of the stabilising device on the metalstrip 200 and the air outlet gap 112 lies in a range of 200 to 800millimetres, preferably in a range of 300 to 500 millimetres.

For realisation of the changed positioning or arrangement of thestabilising device 140 obviously all necessary electrical and pneumaticfeed lines or pipe runs have to be suitably adapted. The same alsoapplies to diverse housing panels. By comparison with the known device100 it can be required to place the mounting devices 130-1, 130-2further apart, for example by 100 millimetres, than in the prior art soas to not only be able to accommodate the stabilising device 140 in theintermediate space between the mounting devices, but also to makepossible horizontal movability thereof with the help of thestabilising-displacing device 145 or to create sufficient space for thatpurpose.

The blow-off device 110 spans a slot 122 through which the metal strip200 is guided. Excess coating material is blown off the surface of themetal strip 200 with the help of the blow-off device.

In order that the blowing-off on the upper side and lower side of themetal strip 200 takes place uniformly it is important that the metalstrip 200 runs through the slot 122 of the blow-off device 110 in apredetermined target centre position, also called centre plane 160, asis symbolised in FIG. 3 in the form of the solid line in X direction.This target centre position is distinguished by, in particular, uniformspacings or spacing distributions from the inner edges of the slot 122of the blow-off device 110. Apart from the desired predetermined targetcentre position, possible undesired actual positions of the metal stripare also illustrated in FIG. 3 as dashed lines. Thus, undesired actualpositions for the metal strip 200 consist of, for example, twistingthereof relative to the target centre position or a parallel shiftthereof in Y direction.

FIG. 4 shows a third possible undesired actual position in which themetal strip 200 is shifted parallelly relative to the target centreposition in X direction, i.e. in width direction.

The electromagnetic stabilising device 140 for its part has a slot 142through which the metal strip 200 is similarly guided. It is alsoapplicable here that the metal strip 200 runs through the slot 142preferably in a predetermined target centre position 160, as shown inFIGS. 3 and 4, so that the forces provided by the electromagneticstabilising device 140 can act in desired manner uniformly on the metalstrip 200 with stabilising effect. The same applies to the slot 142 andthe target centre position, which is also desired there, as previouslystated with reference to FIGS. 3 and 4 for the slot 122 of the blow-offdevice 110.

In addition, a first detecting device 154 for detecting a departure ofthe actual position of the metal strip 200 from a predetermined targetcentre position in the slot 122 of the blow-off device 110 is arrangedbetween the stabilising device 140 and the blow-off device 110.Alternatively, the first detecting device 154 can also be constructedfor detecting the actual position of the metal strip. Moreover, aregulating device 180 is provided for regulating the actual position ofthe metal strip 200 to the predetermined target centre position 128 inthe slot 122 of the blow-off device, as explained above with referenceto FIGS. 3 and 4, by displacement of the blow-off device 110 with thehelp of a blow-off displacing device 115, i.e. by displacing the crossmember 130 at which the blow-off device 110 is suspended. The regulationis carried out in response to the detected departure. If thedetermination of the departure of the actual position from the targetcentre position does not take place in the first detecting device 154,it can also take place, for example, within the regulating device 180.The displacement of the blow-off device 110 is carried out in ahorizontal plane transversely to the transport direction R of the metalstrip as a function of the detected departure of the actual position ofthe metal strip from the predetermined target centre position in theslot 122 of the blow-off device. In other words, if it is establishedthat the metal strip 200 does not run through the slot 122 and thetarget centre position 128, then the blow-off device 110 is displacedwith the help of the blow-off displacing device 115 in such a way thatthe metal strip again runs through the slot 122 of the blow-off devicein the predetermined target centre position 128. The first detectingdevice 154 is so constructed for this purpose that it can preferablydetect all three actual positions of the metal strip 200 departing fromthe target centre position 128 as described above with reference toFIGS. 3 and 4.

The said displacement of the blow-off device 110 should not have anyeffect on the electromagnetic stabilising device 140. For this purpose,the control device 170 is constructed to control thestabilising-displacing device 145 in such a way that the electromagneticstabilising device 140 in the case of a displacement of the blow-offdevice 110 relative to a pass line reference position is not movedtherewith, but can remain in its original location. The pass linereference position 160 denotes a fixedly defined centre plane of thedevice. By contrast, the target centre positions 128 refer to the slots122, 142. The control device 170 accordingly acts on thestabilising-displacing device 145 in such a way that in the event ofdisplacement of the blow-off device 110 the electrical stabilisingdevice 140 executes preferably precisely the opposite movement to theblow-off device 110, i.e. as a result preferably remains at the originallocation thereof.

In order to realise this special form of control for thestabilising-displacing device 145 the control device 170 can evaluatedifferent situations. On the one hand, the control device 170 can beconstructed to carry out displacement of the electromagnetic stabilisingdevice 140 as a function of the departure, which is detected by thefirst detecting device 154, of the actual position of the metal stripfrom the predetermined target centre position of the metal strip in theslot 122 of the blow-off device 110.

Alternatively or additionally, the control device 170 can be constructedto carry out displacement of the electromagnetic stabilising device as afunction of and in opposite direction to the displacement, which isdetected by a second detecting device 155, of the blow-off device 120.The second detecting device 155 serves for detecting the displacement ofthe blow-off device 110 relative to a pass line reference position 160of the device 100.

Finally, in accordance with a further alternative or in addition thecontrol device 170 can be constructed to effect displacement of theelectromagnetic stabilising device 140 in dependence on a detecteddeparture of the actual position of the metal strip from a predeterminedtarget centre position in the slot 142 of the electromagneticstabilising device. A precondition thereof is that a third detectingdevice 156 is present for detecting the said departure of the actualposition of the metal strip from the predetermined target centreposition in the slot 142 of the electromagnetic stabilising device 140.

The first, second and third detecting devices 154, 155, 156 arerespectively constructed to recognise preferably all conceivabledepartures of an actual position of the metal strip from the desiredtarget centre position. Amongst those are, in particular, a (parallel)displacement of the metal strip in X or Y direction or a twisting asexplained above with reference to FIGS. 3 and 4. Correspondingly, thestabilising device 145 and the blow-off displacing device 115 are, inthe case of appropriate control by the regulating device 180 or thecontrol device 170, constructed to move the blow-off device 110 and theelectromagnetic stabilising device 140 in desired manner in horizontalplane transversely with respect to the transport direction R of themetal strip, in particular to displace (parallelly) or rotate about avertical axis of rotation in order to realise transit of the metal stripin the target centre position.

The first and third detecting devices 154, 156 and optionally also thesecond detecting device 155 can be realised in the form of one or moreoptical sensor devices 190. To that extent, the sensor device forms aconstructional unit for the said detecting devices. For preference asensor device 190 is provided for each coil in the electromagneticstabilising device 140. The measurement values of all sensor devices aretypically averaged. The sensor device 190 can also be generally termedspacing detection device.

REFERENCE NUMERAL LIST

100 device

110 blow-off device

112 air outlet gap

115 blow-off displacing device

122 slot of the blow-off device

128 target centre plane

130 cross member

130-1 mounting device

130-2 mounting device

140 stabilising device

142 slot of the stabilising device

145 stabilising-displacing device

150 lateral posts

154 first detecting device

155 second detecting device

156 third detecting device

160 pass line reference position of the device

170 control device

180 regulating device

190 sensor device

200 metal strip

310 coating material

A fixed side

B movable side

d spacing

F force

L longitudinal axis of blow-off device

R transport direction of the metal strip

X width direction of the metal strip in target centre position

Y direction transverse to the plane spanned by the metal strip

1. A device (100) for treating a metal strip (200) after it has exited acoating container (300) with liquid coating material (310), wherein thedevice comprises: a blow-off device (110), which is arranged above thecoating container, with an air outlet gap (112) for blowing excess partsof the still-liquid coating material (310) off the surface of the metalstrip (200) after passage of the metal strip through the coatingcontainer; an electromagnetic stabilising device (140), which isarranged above the blow-off device (110), for stabilising the metalstrip (200) after leaving the coating container and the blow-off device,wherein the stabilising device (140) is so arranged above the blow-offdevice (110) that the spacing (d) between the line of action of themaximum force (F) of the stabilising device on the metal strip (200) andthe air outlet gap (112) lies in a range of 100 to 1200 millimetres; anda horizontal cross member (130) mounted between two vertical lateralposts (150), wherein the blow-off device (110) is secured to and hangsbelow the cross member (130), and wherein the stabilising device (140)between the cross member (130) and the blow-off device issecured—independently of the blow-off device—to the cross member (130)and hangs below the cross member.
 2. The device according to claim 1,wherein the blow-off device (110) is secured by way of a blow-offdisplacing device (115) to the cross member (130), the blow-offdisplacing device (115) being constructed to displace the blow-offdevice (11) in a horizontal plane relative to the cross member (130)and/or to pivot it about its own longitudinal axis; and wherein aregulating device (180) is provided for activating the blow-offdisplacing device (115).
 3. The device (100) according to claim 1,wherein the stabilising device (140) is secured to the cross member(130) by way of a stabilising-displacing device (145), thestabilising-displacing device (145) being constructed to translationallydisplace and/or pivot the stabilising device (140) relative to the crossmember (130) and relative to the blow-off device (110) in the horizontalplane; and wherein a control device (170) is provided for controllingthe stabilising-displacing device (145).
 4. The device (100) accordingto claim 1, wherein the cross member (130) and, together with the crossmember also the blow-off device (110) and stabilising device (140)secured thereto, are mounted at the vertical posts (140) to bevertically displaceable.
 5. The device (100) according to claim 2,wherein a first detecting device (154) is provided for detecting adeparture of the actual position of the metal strip (200) from apredetermined target centre position (128) in a slot (122) of theblow-off device (110); and wherein the regulating device (180) isconstructed for regulating the actual position of the metal strip (200)to the predetermined target centre position of the metal strip (200) inthe slot (122) of the blow-off device (110) by displacing the blow-offdevice (120) with the help of the blow-off displacing device (115) inthe horizontal plane in dependence on the detected departure of theactual position of the metal strip (200) from the predetermined targetcentre position in the slot (122) of the blow-off device (110).
 6. Thedevice (100) according to claim 5, wherein the control device (170) isconstructed for displacing the electromagnetic stabilising device (140)in dependence on the departure, which is detected by the first detectingdevice (154), of the actual position of the metal strip from thepredetermined target centre position of the metal strip (200) in theslot (122) of the blow-off device (110).
 7. The device (100) accordingto claim 3, wherein a second detecting device (155) is provided fordetecting the displacement of the blow-off device (110) relative to apass line reference position (160) of the device (100); and wherein thecontrol device (170) is constructed to control thestabilising-displacing device (145) for displacing the electromagneticstabilising device (140) in dependence on and in opposite direction tothe displacement, which is detected by the second detecting device(155), of the blow-off device (110).
 8. The device (100) according toclaim 3, wherein a third detecting device (145) is provided fordetecting a departure of the actual position of the metal strip (200)from a predetermined target centre position in a slot (142) of theelectromagnetic stabilising device (140); and wherein the control device(170) is constructed to control the stabilising-displacing device (145)to displace the electromagnetic stabilising device (140) in dependenceon a detected departure of the actual position of the metal strip fromthe predetermined target centre position in the slot (142) of theelectromagnetic stabilising device (140).
 9. The device (100) accordingto claim 3, wherein the stabilising-displacing device (145) fordisplacing the electromagnetic stabilising device (140) is arrangedbetween the cross member (130) and the electromagnetic stabilisingdevice (140).